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When a worn or mismatched sprocket causes chain skip, premature wear, or unexpected downtime, the entire drive system suffers. Engineers, fabricators, and serious DIYers who rely on #40 / 08B roller chain drives need a sprocket that holds tight tolerances and resists fatigue under continuous load. This 08B duplex chain sprocket is engineered for exactly those demanding applications — delivering consistent engagement and long service life across a wide range of tooth counts.
Each sprocket is machined from 45# medium-carbon steel and designed to the ISO 08B duplex chain standard with a pitch of 12.7mm (1/2 inch). Available in tooth counts from 10 to 38 teeth, the bore and hub dimensions vary by model — refer to variant options for exact bore sizing. The duplex (double-strand) configuration doubles the load capacity compared to a simplex sprocket of the same pitch, making it well-suited for high-torque or high-speed applications.
Typical use cases include industrial conveyor systems requiring synchronized dual-strand chain drives, agricultural equipment gearboxes using 08B roller chain, and custom DIY power transmission rigs where a compact 12.7mm pitch sprocket is needed for speed reduction or torque multiplication. Long-tail applications include replacement 08B duplex sprocket for go-kart drives, 40-chain duplex sprocket for robotics platforms, and 12.7mm pitch double-strand sprocket for woodworking machinery.
Conforms to ISO 08B double-strand chain dimensions with a 12.7mm pitch, ensuring drop-in compatibility with standard #40 / 08B duplex roller chains used across industrial and DIY applications.
Available in 24 tooth-count variants from 10 to 38 teeth, giving you the flexibility to dial in your exact gear ratio for speed reduction or torque multiplication in your drive system.
Machined from 45# carbon steel for a strong balance of hardness and toughness. The material resists tooth deformation under cyclic loading, extending sprocket service life in continuous-duty drives.
The dual-strand groove profile doubles the chain contact area compared to a simplex sprocket, significantly increasing load capacity and reducing per-strand stress — ideal for high-torque conveyor and machinery drives.
Each tooth is machined to tight tolerances to ensure smooth chain engagement, minimize vibration, and reduce noise during operation — critical for machinery where chain chatter causes wear or measurement errors.
Designed as a direct replacement for worn 08B duplex sprockets on conveyors, agricultural drives, and custom fabrications. Select your tooth count above to match your existing drive ratio without redesigning the system.
| Chain Standard | ISO 08B Duplex (Double-Strand) |
|---|---|
| ANSI Equivalent | #40 Duplex |
| Chain Pitch | 12.7mm (1/2") |
| Number of Strands | 2 (Duplex) |
| Tooth Count Range | 10T – 38T (see variant options) |
| Material | 45# Medium-Carbon Steel |
| Bore Diameter | See variant options |
| Hub Diameter | See variant options |
| Hub Length | See variant options |
| Overall Width | See variant options |
| Surface Finish | Natural / Uncoated (machined surface) |
| Weight | See variant options |
The tooth count determines your drive ratio. Divide the driven sprocket teeth by the driver sprocket teeth to get the reduction ratio. For example, a 10-tooth driver paired with a 30-tooth driven sprocket gives a 3:1 reduction. Select the tooth count that achieves your target output speed or torque based on your input shaft RPM.
Yes. The ISO 08B pitch of 12.7mm is dimensionally equivalent to the ANSI #40 pitch. This sprocket is compatible with both ISO 08B duplex and ANSI #40 duplex roller chains. Always verify the inner link width and roller diameter of your chain against the sprocket groove dimensions before installation.
Bore diameter varies by tooth count — please refer to the variant options or contact us to confirm the bore size for your selected model. If you need a custom bore diameter or keyway, we recommend consulting a local machine shop to bore the sprocket to your shaft specification after purchase.
45# medium-carbon steel provides good mechanical strength but has moderate corrosion resistance in its natural machined state. For outdoor or humid environments, we recommend applying a light coat of chain lubricant or anti-rust spray to the sprocket surface. For highly corrosive environments, consider stainless steel alternatives.
A duplex (double-strand) sprocket engages two parallel chain strands simultaneously, effectively doubling the load-bearing contact area compared to a simplex sprocket of the same pitch and tooth count. This makes duplex configurations the preferred choice for high-torque drives, heavy conveyor systems, and applications where a single-strand chain would be undersized.
Common signs of a worn sprocket include hooked or shark-fin shaped teeth, chain skipping under load, increased vibration or noise during operation, and visible gaps between the chain rollers and sprocket teeth. Replacing the sprocket and chain together is strongly recommended — installing a new chain on a worn sprocket (or vice versa) accelerates wear on both components.
Yes, provided your go-kart or small engine drive uses #40 / 08B duplex roller chain with a 12.7mm pitch. Verify the bore diameter matches your axle or crankshaft diameter, and confirm the tooth count gives you the desired speed ratio. The 45# steel construction handles the cyclic loading typical of small engine applications.
